The present invention relates to a method and an arrangement for adjusting a number of settings in an x-ray imaging apparatus for recurrent mammography examinations, said apparatus comprising at least one x-ray source, a collimator arrangement and compression pedals for positioning and compressing the breast of a patient to be examined. The arrangement comprises: control units for adjusting said number of settings of said x-ray imaging apparatus based on an identity of said person to be examined and data stored in a database, said data including a set of setting-data from at least one recent x-ray examination of said patient, a main control unit communicating with a control unit for adjusting characteristics of x-ray radiations from said x-ray source, a control unit for adjusting the position of said x-ray source, and an identity input device.
The adjustment of an x-ray imaging apparatus and specially a mammogrphic imaging apparatus is normally a time consuming and labourious work, specially for a nurse or the operator responsible of the per-adjustment. For each person to be examined, usually several settings must be modified. The settings include the physical features of the apparatus such as the height of the x-ray source and the breast compression arrangement, respectively, with respect to the physical appearance of the patient, and the x-ray intensity and spectrum, e.g. through adjustment of the amount of power to the radiation source, the current between the anode and cathode of the x-ray tube and filtration of the x-rays.
U.S. Pat. No. 5,349,625 describes an x-ray diagnostics installation for peripheral angiography examinations includes a control unit having an arithmetic unit that, on the basis of subject-related data supplied thereto, effects a pre-setting of the electrical parameters of the installation required for every exposure, plus the step length and the number of steps of the relative adjustment of the exposure unit and the patient support relative to one another, as well as the required diaphragm setting. By virtue of the pre-setting, stress on the patient is reduced, and since the overall time per examination is also reduced, patient throughput can be increased.
In U.S. Pat. No. 4,907,251, a patient positioning device in a medical panorama X-ray photographing apparatus in which after data of the relative position of the subject to the X-ray photographing apparatus supplied from a sensor is compared with data of the relative position of a tomographic zone to the X-ray photographing apparatus thus to produce comparison data which is in turn transmitted to a drive circuit, a tomograph forming assembly and/or the subject is moved from coinciding with each other. The device further includes a comparing arithmetic circuit in which the detected position data of the subject and position data of the tomographic zone are arithmetically compared in order to improve operatability and positioning accuracy. The device furthermore includes a sensor, which is adjustable for angular and vertical setting with the use of sensing position changing means in order to improve adaptability to individualities of the subject.
These documents, however, do not consider the specific problems related to mammography, i.e. placing the breast of the patient in a correct position and compressing it to obtain an even tissue compression for obtaining good resolution.
What is needed is an arrangement that allows an x-ray imaging apparatus, specially an apparatus for mammographic examination, to automatically assume settings specific for a certain person to be examined.
Advantages with the arrangement according to the present invention are that the burden on the operator and the patient reduces and the number of persons which can be examined and the examination flow increase as the pre-adjustment time reduces.
For this reason the initially mentioned arrangement further comprises a device for adjusting collimator slots widths based on information retrieved from said database and/or a position of said pedals. Moreover, the arrangement comprises means to detect the positions of said pedals, a compression sensor for sensing a pressure exerted by said pedals onto said breast and adjusting said pressure and position sensors for positioning said x-ray source. The identity input device is any one of a card reading device, a finger print sensor, a pin-code input device or a keyboard
The invention also relates to a method in initially mentioned arrangement, which is characterised by the steps of: claiming an identity of said patient, upon receiving said identity retrieving a set of setting data from at least one last x-ray examination of said person and/or a position of said pedals, and adjusting collimator slots"" widths based on said information. According to the method under a first time examination of said person, a substantially manual adjustment is carried out and results of said substantially manual adjustment are registered for later examinations.